全文获取类型
收费全文 | 571篇 |
免费 | 39篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 24篇 |
妇产科学 | 24篇 |
基础医学 | 44篇 |
口腔科学 | 18篇 |
临床医学 | 65篇 |
内科学 | 117篇 |
皮肤病学 | 17篇 |
神经病学 | 9篇 |
特种医学 | 134篇 |
外科学 | 52篇 |
综合类 | 10篇 |
预防医学 | 18篇 |
眼科学 | 4篇 |
药学 | 17篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 1篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 20篇 |
2014年 | 12篇 |
2013年 | 28篇 |
2012年 | 14篇 |
2011年 | 20篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 17篇 |
2007年 | 36篇 |
2006年 | 24篇 |
2005年 | 21篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 47篇 |
1997年 | 46篇 |
1996年 | 22篇 |
1995年 | 23篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 9篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有625条查询结果,搜索用时 16 毫秒
51.
Kee F; McDonald P; Kirwan JR; Patterson CC; Love AH 《QJM : monthly journal of the Association of Physicians》1997,90(11):669-676
To determine the factors that influenced doctors' prioritization and
decisions on safe waiting time for coronary artery bypass surgery, 50
'paper patients', based on a random sample of cases who actually had
surgery, were assessed by 33 clinicians. We used linear regression models
to reflect the impact of clinical and non-clinical 'cues' on safe waiting
time and priority decisions. The benefits of surgery tended to be
over-estimated. For example, the average perceived gain in life expectancy
for patients with left main-stem disease was 6.74 years. However, models
incorporating only the perceptions of benefit as independent variables
(i.e. the anticipated symptom reduction, MI risk reduction and life
expectancy extension), had only modest explanatory power (mean R2 was 0.55
for safe waiting time, and 0.56 for priority decisions). Models which
incorporated perceptions of benefit and the cases' clinical and
non-clinical characteristics had generally much higher explanatory power
(mean R2, 0.83 and 0.86, respectively). Lifestyle and demographic variables
had much less impact on the doctors' judgements than the major clinical
cues of angina severity and left main-stem stenosis. Demographic and
lifestyle cues had different impacts on safe waiting time and priority for
about 25% of doctors.
相似文献
52.
Kee F; McDonald P; Kirwan JR; Patterson CC; Love G 《QJM : monthly journal of the Association of Physicians》1997,90(2):117-123
In a clinical judgement analysis, we used linear regression models to
reflect the impact of clinical and non-clinical cues on priority decisions,
by comparing the stated prioritization policies of 30 clinicians with their
actual policies as revealed by an appraisal of 50 'paper patients'.
Correspondence was modest for some cues, e.g. 25 doctors said they
accounted for age, but age only had a significant bearing in the derived
decision models of two doctors. Correspondence between the derived and
expressed weights was greatest for clinical angina grade and the presence
of left main stem stenosis. Correlation between the rank order of
importance between the two models was poor for most of the cues, and
statistically significant only for smoking. However, stated policies made
it appear that lifestyle factors such as smoking habit would influence
prioritization decisions for most clinicians but policies derived from
actual prioritization decisions seldom related to lifestyle or demographic
variables. There were significant differences in the degree of correlation
between the two models according to the experience of the clinician.
However, correspondence was not significantly better for doctors with
cardiological training than those without. The overall contribution of
demographic and lifestyle factors to decision making appears to be small,
suggesting that they should be omitted from prioritization guidelines.
相似文献
53.
54.
Ageing appearance in China: biophysical profile of facial skin and its relationship to perceived age
AE Mayes PG Murray DA Gunn CC Tomlin SD Catt YB Wen LP Zhou HQ Wang M Catt SP Granger 《Journal of the European Academy of Dermatology and Venereology》2010,24(3):341-348
Background Perceived age is important to women and is a primary driver for topical product use and facial cosmetic surgery. Changes in facial features and biophysical skin parameters with chronological age and their associations with perceived age have not been described in Asian populations. Objective To investigate the relationship between biophysical properties of the skin, visual features of skin ageing and perceived facial age in Chinese women. Methods Facial photographs were collected of 250 Chinese women, aged 25–70 years in Shanghai, China. The perceived facial age was determined and related to the chronological age for each participant and to a range of visual assessments of skin appearance and objective biophysical measurements of the skin. The profile of changes in these parameters with age was investigated together with the differences in those parameters for women judged to look younger than their chronological age and those judged to look older than their chronological age. Results Large discrepancies in perceived age (up to 29 years) were found in women of the same chronological age. Each objective skin measure and visual assessment parameter had a stronger correlation with perceived age than with chronological age. The strongest relationships to perceived age were for wrinkles and hyperpigmentation. Skin colour, hydration and trans‐epidermal water loss (TEWL) had weaker associations with perceived age. Women judged to look older than their chronological age had significantly higher scores than those judged to look younger for coarse wrinkles and hyperpigmentation across all age groups. The appearance differences between these groups were evident in composite facial images of the same average chronological age. Conclusions We have identified the skin attributes which differ with perceived age in Chinese women. Perceived age is a better measure of the biological age of facial skin than is chronological age in this population. 相似文献
55.
Miriam Hoekstra Mathijs Vogelzang José T Drost Marcel Janse Bert G Loef Iwan CC van der Horst Felix Zijlstra Maarten WN Nijsten 《BMC medical informatics and decision making》2010,10(1):5
Background
Potassium disorders can cause major complications and must be avoided in critically ill patients. Regulation of potassium in the intensive care unit (ICU) requires potassium administration with frequent blood potassium measurements and subsequent adjustments of the amount of potassium administrated. The use of a potassium replacement protocol can improve potassium regulation. For safety and efficiency, computerized protocols appear to be superior over paper protocols. The aim of this study was to evaluate if a computerized potassium regulation protocol in the ICU improved potassium regulation. 相似文献56.
Background
Pneumocystis jiroveci pneumonia (PCP) is an important opportunistic infection among immunosuppressed patients, especially in those infected with human immunodeficiency virus (HIV). The clinical presentation of PCP in immunosuppressed patients have been well-reported in the literature. However, the clinical importance of PCP manifesting in the setting of an immunorestitution disease (IRD), defined as an acute symptomatic or paradoxical deterioration of a (presumably) preexisting infection, which is temporally related to the recovery of the immune system and is due to immunopathological damage associated with the reversal of immunosuppressive processes, has received relatively little attention until recently. 相似文献57.
BACKGROUND: Transfusion-associated graft-versus-host disease can be prevented by gamma radiation of blood components. The increased use of blood components donated for patients by their family members has resulted in an increased demand for the storage and handling of irradiated units, and the ability to freeze the cells would allow storage beyond their current expiration date. STUDY DESIGN AND METHODS: To assess the effect of freezing and deglycerolization on irradiated red cells, studies of autologous radiolabeled red cell recovery were performed using normal volunteers. Each unit of CPDA-1 red cells was immediately divided into two equal volumes. Further handling of each half was identical except that one was irradiated (3500 cGy). The units were grouped under three protocols: I, irradiated on Day 0 and frozen on Day 5 (n = 4); II, irradiated on Day 7, rejuvenated, and frozen on Day 14 (n = 5); and III, irradiated on Day 14, rejuvenated, and frozen on Day 18 (n = 3). All cells were frozen for 3 to 10 months at -80 degrees C. RESULTS: Irradiated and control units showed no significant differences in supernatant potassium or hemoglobin. Autologous 24-hour posttransfusion recoveries (mean +/− SD) for the three groups were: I, 89.7 +/− 5.6 percent (control, 90.6 +/− 3.2%); II, 85.3 +/− 5.7 percent (control, 83.7 +/− 3.0%); and III, 79.5 +/− 1.4 percent (control, 82.6 +/− 5.2%). CONCLUSION: Irradiated red cells can be frozen after being stored under various conditions and can still meet established guidelines requiring 75-percent recovery 24 hours after transfusion. 相似文献
58.
Tanyuksel M Ulukanligil M Guclu Z Araz E Koru O Petri WA 《The American journal of tropical medicine and hygiene》2007,76(4):723-724
We report two cases (a 36-year-old woman and 2-year-old girl) infected with Entamoeba moshkovskii in Turkey. Entamoeba moshkovskii was identified and distinguished from the morphologically identical parasites E. histolytica and E. dispar by a nested polymerase chain reaction and restriction fragment length polymorphism analysis of the small subunit ribosomal DNA gene. 相似文献
59.
Gazitt Y; Reading CC; Hoffman R; Wickrema A; Vesole DH; Jagannath S; Condino J; Lee B; Barlogie B; Tricot G 《Blood》1995,86(1):381-389
High-dose therapy with autologous marrow or peripheral blood stem cell (PBSC) rescue has been extensively applied in the treatment of multiple myeloma (MM) patients during the past 10 years resulting in improved event-free and overall survival when compared with standard chemotherapy. However, relapses are common and cure is unlikely in the majority of patients. Because both bone marrow and PBSCs are contaminated with myeloma cells it is conceivable that relapse after autotransplantation originates at least in part from autografted tumor cells. In this study, mobilized PBSCs were examined for the presence of myeloma cells based on immunophenotyping and sensitive polymerase chain reaction (PCR)-based techniques. In addition, CD34+ Lin- Thy+ stem cells were purified from mobilized PBSC harvests of 10 MM patients by sequentially using counterflow elutriation centrifugation, treatment with phenylalanine methylester, and flow sorting, using 5-parameter gating (propidium iodide, forward scatter, side scatter, CD34+ v Lin- and CD34+ v Thy+). Virtually all mobilized unsorted PBSC preparations contained myeloma cells in sufficient quantities (range, < 0.01 to > 10%) potentially causing a disease relapse. Stem cell purification led to an overall enrichment by about 50-fold in all 10 patients; approximately 90% of the final cell population expressed CD34+ Lin- Thy+ with no evidence of myeloma cell contamination based on flow cytometric analysis of CD38bright cells (< 0.1%). Quantitative PCR amplification of patient-specific complementarity determining region III (CDRIII) DNA sequences showed depletion of clonal B cells by 2.7 to 7.3 logs, with the highest log reduction noted in the samples initially containing the most tumor cells. Our results show that purification of CD34+ Lin- Thy+ cells depletes myeloma cells to undetectable levels from up to 10% present in unsorted PBSCs, thus offering a tool to investigate whether MM relapse after autotransplantation can be reduced markedly. 相似文献
60.
F MAROTTA R BARRETO CC WU Y NAITO F GELOSA A LORENZETTI M YOSHIOKA E FESCE 《Journal of digestive diseases》2005,6(4):193-197
OBJECTIVE: The aim of this study was to test the effect of gut manipulation by either novel synbiotics or by metronidazole on either endotoxemia or the severity of liver damage in the course of acute pancreatitis from alcohol ingestion. METHODS: Sprague–Dawley rats were fed for 1 week through an intragastric tube a liquid diet with either: (i) 1 mL t.i.d. of a mixture of synbiotics (Lactobacillus acidophilus, Lactobacillus helveticus and Bifidobacterium in an enriched medium); (ii) 20 mg/kg t.i.d. metronidazole; or (iii) standard diet. Then, acute pancreatitis was induced by caerulein and when the disease was full‐blown, rats were fed an alcohol‐rich diet. Synbiotic and metronidazole treatment was given for a further 2 weeks. Transaminase and endotoxemia levels were measured before treatment, after 6 h, after 24 h and 2 weeks later, at the time the rats were killed. Liver samples were obtained for histological analysis. RESULTS: Synbiotics but not metronidazole improved the acute pancreatitis‐induced increase in endotoxemia and transaminase levels. The addition of alcohol worsened these variables to a limited extent in the synbiotic‐treated group, while metronidazole had a negative effect on liver damage. CONCLUSIONS: Gut flora pretreatment with synbiotics was able to effectively protect against endotoxin/bacterial translocation, as well as liver damage in the course of acute pancreatitis and concomitant heavy alcohol consumption. The beneficial effect of synbiotics on liver histology seems to be correlated with endotoxemia. Metronidazole did not produce such a beneficial effect; in fact, it further worsened liver damage when alcohol was added to the background of ongoing acute pancreatic inflammation. 相似文献